1. Field of the Invention
This invention relates to a liquid nonionic surfactant combination which is pourable at low temperatures and which is stable in storage over a wide temperature range from -10.degree. to +40.degree. C.
2. Statement of Related Art
Surfactant combinations of the type in question are used in particular as liquid concentrates together with so-called washing alkalis and are particularly suitable for the washing of oil-stained textiles and working apparel in laundries. Liquid concentrates which can be automatically metered are particularly valuable for an application such as this. In addition to the properties mentioned, liquid concentrates are virtually unaffected in their viscosity behavior by variations in temperature.
Known pourable concentrates used for purposes of the type in question typically contain solvents, more particularly low molecular weight alcohols, to guarantee the necessary low-temperature stability. In many cases, low molecular weight polyglycols or polypropylene glycol are added to them to improve not only their low-temperature stability, but also their viscosity behavior in the required manner. However, neither addition makes any contribution to the washing effect.
Accordingly, the problem addressed by the present invention was to provide a corresponding liquid concentrate which, despite no additions of solvent, would be stable over a relatively wide temperature range and which would be easy to meter at various temperatures without significant changes in viscosity. At the same time, the washing and cleaning properties, particularly with respect to oil- and grease-containing soil, would not be reduced by comparison with known leading products, but instead would be fully maintained or even increased. This problem has been solved by the invention described in detail hereinafter,